package com.clothing.utils;

import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class MathUtils
{
    private static ScriptEngine jse = new ScriptEngineManager()
            .getEngineByName("JavaScript");

    private final static char[] digits = { '0', '1', '2', '3', '4', '5', '6',
            '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
            'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
            'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
            'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
            'x', 'y', 'z' };

    private final static Map<Character, Integer> digitMap = new HashMap<Character, Integer>();

    static
    {
        for (int i = 0; i < digits.length; i++)
        {
            digitMap.put(digits[i], i);
        }
    }

    /**
     * 支持的最大进制数
     */
    public static final int MAX_RADIX = digits.length;

    /**
     * 支持的最小进制数
     */
    public static final int MIN_RADIX = 2;

    public static String runStringExp(String exp)
    {
        String result = "";
        try
        {
            return jse.eval(exp).toString();
        }
        catch(ScriptException e)
        {
            result = "error-" + e.getMessage();
            return result;
        }
    }

    static NumberFormatException forInputString(String s)
    {
        return new NumberFormatException("For input string: \"" + s + "\"");
    }

    /**
     * 将字符串转换为长整型数字
     * 
     * @param s
     *            数字字符串
     * @param radix
     *            进制数
     * @return
     */
    public static long toNumber(String s, int radix)
    {
        if (s == null)
        {
            throw new NumberFormatException("null");
        }

        if (radix < MIN_RADIX)
        {
            throw new NumberFormatException("radix " + radix
                    + " less than Numbers.MIN_RADIX");
        }
        if (radix > MAX_RADIX)
        {
            throw new NumberFormatException("radix " + radix
                    + " greater than Numbers.MAX_RADIX");
        }

        long result = 0;
        boolean negative = false;
        int i = 0, len = s.length();
        long limit = -Long.MAX_VALUE;
        long multmin;
        Integer digit;

        if (len > 0)
        {
            char firstChar = s.charAt(0);
            if (firstChar < '0')
            {
                if (firstChar == '-')
                {
                    negative = true;
                    limit = Long.MIN_VALUE;
                }
                else if (firstChar != '+')
                {
                    throw forInputString(s);
                }

                if (len == 1)
                {
                    throw forInputString(s);
                }
                i++;
            }
            multmin = limit / radix;
            while (i < len)
            {
                digit = digitMap.get(s.charAt(i++));
                if (digit == null)
                {
                    throw forInputString(s);
                }
                if (digit < 0)
                {
                    throw forInputString(s);
                }
                if (result < multmin)
                {
                    throw forInputString(s);
                }
                result *= radix;
                if (result < limit + digit)
                {
                    throw forInputString(s);
                }
                result -= digit;
            }
        }
        else
        {
            throw forInputString(s);
        }
        return negative ? result : -result;
    }

    /**
     * 将长整型数值转换为指定的进制数（最大支持62进制，字母数字已经用尽）
     * 
     * @param i
     * @param radix
     * @return
     */
    public static String toString(long i, int radix)
    {
        if (radix < MIN_RADIX || radix > MAX_RADIX)
        {
            radix = 10;
        }
        
        if (radix == 10)
        {
            return Long.toString(i);
        }

        final int size = 65;
        int charPos = 64;

        char[] buf = new char[size];
        boolean negative = (i < 0);

        if (!negative)
        {
            i = -i;
        }

        while (i <= -radix)
        {
            buf[charPos--] = digits[(int) (-(i % radix))];
            i = i / radix;
        }
        buf[charPos] = digits[(int) (-i)];

        if (negative)
        {
            buf[--charPos] = '-';
        }

        return new String(buf, charPos, (size - charPos));
    }

    private static String digits(long val, int digits)
    {
        long hi = 1L << (digits * 4);
        return toString(hi | (val & (hi - 1)), MAX_RADIX).substring(1);
    }

    /**
     * 以62进制（字母加数字）生成19位UUID，最短的UUID
     * 
     * @return
     */
    public static String uuid()
    {
        UUID uuid = UUID.randomUUID();
        StringBuilder sb = new StringBuilder();
        sb.append(digits(uuid.getMostSignificantBits() >> 32, 8));
        sb.append(digits(uuid.getMostSignificantBits() >> 16, 4));
        sb.append(digits(uuid.getMostSignificantBits(), 4));
        sb.append(digits(uuid.getLeastSignificantBits() >> 48, 4));
        sb.append(digits(uuid.getLeastSignificantBits(), 12));
        return sb.toString();
    }
    
    /** 
     * 计算两点之间距离 
     * @param start 
     * @param end 
     * @return 米 
     */  
    public static double getDistance(double startLat, double startLon, double endLat, double endLon)
    {
        double pi = Math.PI / 180;
        
        double lat1 = pi * startLat;
        double lat2 = pi * endLat;

        double lon1 = pi * startLon;
        double lon2 = pi * endLon;

        // 地球半径 
        double R = 6370996.81;

        // 两点间距离米
        double d = Math.acos(Math.sin(lat1) * Math.sin(lat2)
            + Math.cos(lat1) * Math.cos(lat2) * Math.cos(lon2 - lon1)) * R;

        return d;
    } 

    public static void main(String[] args) throws UnsupportedEncodingException
    {
//        long t = System.currentTimeMillis();
//        System.out.println(uuid());
//        System.out.println(System.currentTimeMillis() - t);
        double d =getDistance( 37.480563,121.467113, 37.480591,121.467926 );
        System.out.println(d);
    }
}